Tidal Disruption Event Demographics with the Zwicky Transient Facility: Volumetric Rates, Luminosity Function, and Implications for the Local Black Hole Mass Function

September 2023 • 2023ApJ...955L...6Y

Authors • Yao, Yuhan • Ravi, Vikram • Gezari, Suvi • van Velzen, Sjoert • Lu, Wenbin • Schulze, Steve • Somalwar, Jean J. • Kulkarni, S. R. • Hammerstein, Erica • Nicholl, Matt • Graham, Matthew J. • Perley, Daniel A. • Cenko, S. Bradley • Stein, Robert • Ricarte, Angelo • Chadayammuri, Urmila • Quataert, Eliot • Bellm, Eric C. • Bloom, Joshua S. • Dekany, Richard • Drake, Andrew J. • Groom, Steven L. • Mahabal, Ashish A. • Prince, Thomas A. • Riddle, Reed • Rusholme, Ben • Sharma, Yashvi • Sollerman, Jesper • Yan, Lin

Abstract • We conduct a systematic tidal disruption event (TDE) demographics analysis using the largest sample of optically selected TDEs. A flux-limited, spectroscopically complete sample of 33 TDEs is constructed using the Zwicky Transient Facility over 3 yr (from 2018 October to 2021 September). We infer the black hole (BH) mass (M BH) with host galaxy scaling relations, showing that the sample M BH ranges from 105.1 M to 108.2 M . We developed a survey efficiency corrected maximum volume method to infer the rates. The rest-frame g-band luminosity function can be well described by a broken power law of $\phi ({L}_{g})\propto {\left[{\left({L}_{g}/{L}_{\mathrm{bk}}\right)}^{0.3}+{\left({L}_{g}/{L}_{\mathrm{bk}}\right)}^{2.6}\right]}^{-1}$ , with L bk = 1043.1 erg s-1. In the BH mass regime of 105.3 ≲ (M BH/M ) ≲ 107.3, the TDE mass function follows $\phi ({M}_{\mathrm{BH}})\propto {M}_{\mathrm{BH}}^{-0.25}$ , which favors a flat local BH mass function ( ${{dn}}_{\mathrm{BH}}/d\mathrm{log}{M}_{\mathrm{BH}}\approx \mathrm{constant}$ ). We confirm the significant rate suppression at the high-mass end (M BH ≳ 107.5 M ), which is consistent with theoretical predictions considering direct capture of hydrogen-burning stars by the event horizon. At a host galaxy mass of M gal ~ 1010 M , the average optical TDE rate is ≈3.2 × 10-5 galaxy-1 yr-1. We constrain the optical TDE rate to be [3.7, 7.4, and 1.6] × 10-5 galaxy-1 yr-1 in galaxies with red, green, and blue colors.


IPAC Authors

Ben Rusholme

Chief Engineer